Mechanical drive



B. A. scHwARz ET Al.

MECHANICAL DRIVE Oct. 14, 194.1. 2,258,814

Filed Dec. 16, 1959 2 Sheets-'Sheet `l Mii.

95 ttornegs @www Oct- 14, 1941. B. A. SCHWARZ ETYAL 2,258,814

MECHANICAL DRIVE y FiledDec. 16, 1959 2 Sheets-Sheet 2 15.9 /6/ l l ,5.9 7 T 143 2.9 f I 1 4l 4g? i; 7 45 3.3;*

W /2/ if? 93 93 .7 7

:inventors f e'fffwJc//mffzlli muws Patented oci. 14, 1941 y :zessen MECHANICAL DRIVE Motors Corporation, Detroit, Mich.,

tion of Delaware a corpora- Application December 16, 1939, Serial No. 369,530

(Cl. 'lli-10) 7 Claims.

The present invention relates to a mechanical drive and more specifically to mechanical means for converting straight line movement into rotary movement to index a rotary member.

Mechanical drive Vand indexing mechanisms of the above type are particularly adaptable for rotating and indexing the tuning device of radio receivers in order to tune the receiver rapidly to a predetermined broadcast station. The combination of the mechanical drive and indexing mechanism when connectedV to actuate the tuning device of a radio receiver is usually known as an automatic tuning mechanism.

On small receivers such as those used on automobiles, where, thistype of tuning mechanism is particularlyl desirable, the mechanism must be small so thatvit may be included in the receiver housing. The parts of the mechanism must be suiciently strong to prevent bending or misalignment in order to obtain accurate tuning. There must also be provided means whereby the indexing mechanism may be conveniently adjusted so that' the tuning device may be indexed to different positions to vary the selection of broadcast stations to suit the location in which the receiver is operated.

An object of the present invention is to provide a compact, sturdy and inexpensive mechanical drive mechanism which may be included as part of a radio receiver assembly, whereby the receiver may be tuned to any one of a plurality of preselected broadcast stations by merely depressing a push button.

Another1 object is to provide convenient means associated with the tuning mechanism whereby the tuning mechanism may be adjusted by means of one hand only to change the selection of broadcast stations.

The means by which the above and associated objects are accomplished are described in the following specification and illustrated in the accompanying drawings, in which:

Figure l is a front elevation of the control panel ci a radio receiver provided with controls for the tuning mechanism as well as other controls therefor.

Flguie 2 is a top plan View of the tuning mechanisxn with some of the parts broken away to show details thereof.

Figure 3 is a vertical sectional view taken on line 3 3 of Figure 2.

Figure 4 is a front elevation of the tuning mechanism with the control panel broken away and some of the parts of the tuning mechanism broken away and others shown in section to show further details of the mechanism.

Figure 5 is a perspective view of one ci the parts of the mechanism.

As shown in Figures 2 Yto 4, the tuning mechanism is supported in a frame indicated at l comprising end plates 3 and 5 and upper and lower plates 'l and il, rigidlybolted together by nuts H threaded on the ends of bolts I3 which extend through the ends of the upper and lowerplates and through the end plates. The frame I may be supportedl on a radio receiver chassis, not shown, the receiver and frame being suitably mounted behind a control panel shown at l5 which is provided with openings through which control elementsextend for manual operation. These elements consist of a plurality of` push buttons l1 for actuating individual mechanical drive and indexing mechanisms associated with thetuning device of the'receiving set, a manually rotatable tuning knob i9 for the tuning .device in the conventional manner, a volumecontrol knob 2|, and a control knob-23 by which any or all of the mechanical indexing means are adjusted so that any desired broadcasting frequency may be tuned in accurately upon depressing any one push button. A large opening 25 is shown in the panel l5 in which a grill 2 is shown which covers the opening in the radio speaker, not shown, which is associated with the receiver.

ie tuning device associated with the receiving set is enclosed-in a housing 29 provided with end` brackets Si by which it is fixed tothe upper plate 'i of the'frarne I by means `of the screws 32 and 33 and bolts i3 extending through these brackets. -A tuning shaft 35 by which lthe tuning device is adjusted is rotatably supported in a bearing v3tllccated inthe housing. The tuning shaft is limited to av definite angle of rotary movement by conventional stop means, not shown, associated-with the tuning mechanism. A gear 3l, iixed by means of a set screw 38 on the end of the shaft 35, is driven by a gear 65 of larger pitch diameter meshing therewith and fixed to a shaft 'H which is rotated in either direction by mechanical drive and indexing mechanism, to be described later. The tuning shaft 35 may also be rotated by the manually rotatable control knob i9 fixed on the outer end of a shaft 39, the inner end of which is rotatably supported in a U-shaped bracket lll fixed to the housingl 29. A worm 43 is fixed on the shaft portion between the legs of the bracket il and meshes with a, Worm wheel 45 supported adjacent an annular surface 45 of the tuning shaft 35. Y

A clutch mechanism is supported on the tuning shaft 35 between the worm wheel 45 and the gear 31 and includes two clutch discs 41 and 49 rotatably mounted on the shaft adjacent the worm wheel and a hub to which is fixed a cup member 53 and a disc 55. The cup member 53 has an annular surface portion 54 adjacent the disc 41 and is fixed to the gear 31 by screws 51. A helical compression spring 59 placed between the discs 49 and 55 normally urges the discs 49 and 41 toward the worm wheel 43, thereby urging it into frictional driving and holding engagement with the annular surface 46 on the tuning shaft so that rotation of the worm 43 by the manual tuning knob I9 causes rotation of the tuning shaft by the worm wheel. The clutch mechanism, when so engaged with the worm wheel 45, also acts as a holding means to prevent rotation of the tuning shaft 35 and the shaft 1| operatively connected thereto by the gears 65 and 31 on account of the irreversibility of the worm gearing. It will be apparent that any form of gearing having irreversible characteristics may be substituted for the worm gearing shown. The clutch mechanism may be disengaged, however, to allow rotation of the tuning shaft 35 by the shaft 1| by an annular electromagnetic winding 6| located in the space between the hub 5| and cup 53 which is provided with flexible end connections 62 and 63 extending outward through aligned openings inpressing the spring 59 and releasing the force exerted by the spring 59 normally tending to hold the worm wheel in engagement with the annular surface 45 of the tuning shaft 35. Disengagement of the Worm wheel from the tuning shaft allows the tuning shaft 35 to be rotated with respect to the Worm wheel 45 by the shaft 1| which is operatively connected thereto by the gears 65 and 31 previously mentioned.

The gear B5 is provided with a tongue portion 61 extending into a slot 69 of the shaft 1| which is supported in a bushing 13 rotatable in an opening 15 in the end plate 5. A nut 11 threaded on the end of the shaft prevents outward movement of the gear with respect to the shaft. The other end of the shaft 1| is supported by a bushing 19 having a tongue also extending into the slot 69 of the shaft which prevents it from rotating with respect thereto. The bushing 19 is rotatably mounted in an opening 8| in the end plate 3 and is also capable of moving axially in this opening. An insulating washer 82 is pressed on the inner end 83 of the bushing which is turned to a smaller diameter. This washer controls an electric switch located adjacent thereto which will be referred to later. The outer end of the bushing is threaded at 84 on which is screwed an internally threaded hub 85 to which is fixed a gear 81 by which the bushing is screwed axially in either direction when the gear is rotated and the shaft is prevented from rotating. Nuts 88 are threaded on the outer end of the shaft 1| to limit outward movement of the gear 81 with respect to the shaft. A plurality of pinions 89 and sleeves 9| are rotatably mounted on the shaft 1| between the bushings 13 and 19, the sleeves being ylocated between the pinions in order to space them axially with respect to each other. Pinion washers 93 having tongues 95 extending into the slot 69 of the shaft are placed on either side of each pinion between the ends of the sleeves and also between the bushing 19 supporting one end of the shaft and between a spring washer 91 and a collar 99 located on the shaft adjacent the bushing 13 supporting the other end of the shaft. The spring Washer 91 is shown compressed in Figure 4, but is bowed as shown in Figure 5 when not compressed. With the structure described above, movement of the bushing axially inward on the shaft increases the endwise frictional force on the parts carried on the shaft to connect the pinions, which are rotatably mounted on the shaft, to the pinion washers which are non-rotatably mounted on the shaft. With the above mentioned .parts in this position, the pinions are thus operatively connected to rotate with the shaft. Movement of the bushing axially outward on the shaft decreases the endwise frictional force between these parts to a small value, determined only by the axial force exerted by the spring washer 99, and allows the pinions to be rotated with respect to the pinion washers and the shaft. Axial movement of the bushing 19 in either direction with respect to the shaft is accomplished by the gear 81 threaded thereon when the shaft 1| and bushing 19 non-rotatably connected thereto are prevented from rotating and the gear is rotated in either direction which screws the bushing inward or outward with respect to the shaft 1|.

The control knob 23 previously mentioned, together with the following means operatively connected thereto, provides convenient means by which the gear 31 may be rotated in either direction to operatively connect the pinions to the shaft or allow them to be disconnected from the shaft. As best shown in Figure 4, the control knob 23 is fixed to a shaft |0| rotatably supported about an axis at right angles to the shaft 1| in the bore |03 of a housing |05 which is screwed into a bushing |01 fixed in an opening |09 in the lower flange of the panel |5. A spring ||3 located on the shaft has one end in contact with the end ||5 of the counterbore ||6 of the housing and its opposite end in contact with a collar |1 fixed axially with respect to the shaft |9| by a spring ring ||8 and therefore serves to project the shaft and control knob outwardly for manual operation and to maintain a pinion |28 xed on the upper end of the shaft |03 out of mesh with the gear 81. Inward movement of the control knob meshes the pinion |29 with the gear 81 and when the knob is rotated in one direction or the other the gear 81 will be rotated in one direction or the other with respect to the bushing 19 to screw it inwardly or outwardly axially with respect to the shaft 1| to operatively connect or disconnect the pinions with the shaft 1| as described above.

Each of the individual mechanical indexing mechanisms is operatively connected to one of the pinions 89 to cause it to be rotated in either direction to a given angular position when the push button actuating this mechanism is depressed. Each of these mechanisms comprises pairs of racks |2I, each of which is slidably mounted in vertically aligned transverse grooves |23 in the upper and lower plates 1 and 9 of the frame. Each rack of a pair meshes with a pinion at opposite sides thereof and accordingly the racks move linearly in the grooves |23 in opposite directions when the pinion 89 is rotated.

Actuating' meansfor each pair of racksfcomprises apush plate |25 and oneA of the push buttons 15 fixed on theA outer end of a shaft. f2.1 movable.- axially with respect to. a pair of. racks. The inner end of. each of. these shafts. |21' is slidably mounted in openings. |529; in a. plate |31 extending: vertically between the front faces of the upperV and' lower plates and xed thereto by cap: screws |33. vertically aligned'. slotsv |535 are provided. in; the plate l`3-| above and' belowv the shaft openings |29? so that: the ends of the racks |2'| may move therethrough and becontacted and moved linearly by theY push plates when they are. moved inwardly' by the push buttons: The plate |3| has a horizontal flange |31 atits. upper extremityV tol whichV isi fixed by screws |39 the horizontal end projections. |4| of a member |43 having a verticalA fia-nge |:45- spaced from the plate |3|. The. member |43l is also provided with a lower horizontal ange |41 which. extends inwardly and is attached by means of the bolts i3 to the ends of the lower plate 9 of the frame I. The vertical fiange |45 of the member |43 has openings M9 in axial alignment with the shaft opening-s |29 in which thev pushbuttons are slidably mounted. Helical compression springs |5| are located on each shaft |21 between the plate |3| and. the push plates |25 to normally hold the shafts, push plates and push buttons outwardly away from the racks |2.| and in the position shown in Figures 2. and- 3 in wh-ich the push plates are shown in contact with. the peripheral inturned flanges |53 of the. openings |49/ in the vertical flange |45 of the member |43. The lower ends of the: push plates are provided with integral lugs |55 which project, downward into transverse slots |51 in the lower flange |41 of the member |43 to prevent rotation of the push plates and shafts Electrical control means actuated by each push button and by the control knob 23 are provided to allow or prevent rotation of the tuning shaft and shaft 1| by connecting or disconnecting the electromagnetic winding to a source of energy., This means comprises an insulating strip |59 extending horizontally between and fixed to both of the. upper horizontal projections |4'| of the member |43 by screws |6.|. Spring contacts |63 are fixed to the strip |59 by rivets |65 so that each is in a' position to be contacted by a respective push plate when it is moved inwardly a slight distance. Each of the contacts is connected to the conductor |61 which is connected to the connector 62 of the electromagnetic winding 6|; the other connector 63 is connected by a conductor |69 toa blade |19 of a switch indicated at |8|.. This switch comprises a bracket |83 fixed to the end plate 3 by a screw |85 which supportsv the switch blade |19 and another blade |81v arranged parallel thereto. Adjacent ends of these blades are clamped between insulating members |89 which are fixed to the bracket |33 by rivets |9| as best shown in Figure 2. The free ends of these blades extend inwardly toward the insulating` washer 82 fixed to the bushing 19, the end of the blade |81 normally bearing on the outer annular surface of the washer. These blades are provided with contacts |93 and |95 which are held in electric contact with each other when the bushing is moved axially inward on the shaft to connect the pinions 89 to the shaft 1| and are separated when the bushing is moved axially outward on the shaft to disconnect the pinions from the shaft. The blade |81 is connected to one terminal of a battery |91 by a conductor |99', and. the other terminal of' the battery is. connectedf to. the. bracket |83. by a conductor 20|'.

Operation With the parts in their normal position as shown and described, the tuning shaft is rotated by a given angular position by depressing one of the push buttons |1. Initial' inward movement of the push button andv its respective push plate |25 causesv the push plate4 to establish an electrical contact with the spring contact |53 locatedY adjacent thereto whereby a circuit is completed between the battery |91 and the. electromagnetic winding 6|' to disconnect the worm wheel from the tuning shaft 35I to allow the shaft to rotate with respect to the worm wheel. Current flows in. this circuit from the battery |91 to the frame I' and push plate |25 by the conductor 29|, thence. through the spring contact |53' to the winding 61| and from the winding to the switch |8| by the .conductor |69. The switch contacts |93 and |95 are closed as shown, and the current flows through these contacts and back to the battery through the. conductor |99. Further inward movement' of the push plate causes it to come into contact and move one or the other ofa pair of racks inwardly which rotates the pinion 89', shaft 1|v and therefore rotates the tuning shaft 35 in the opposite direction at greater speed .on account. of its geared connection with the shaft 1| consisting of the large gear fixed' to the shaft 1| and the small gear 31 fixed to the tuning shaft 35. Rotation of the pinion likewise causes the other rack to move outward toward the inwardly moving push plate coming into contact therewith which stops movement of all the above named-partsA in a denitev position,l the tuning shaft position being such that the radio receiver is tuned to a certain broadcast station. Upon release ofthe push button the spring |5| returns the push plate and push button to its normal' projected position and breaks the circuit connection to the winding 6| which allows the worm wheel to be reengaged with the tuning shaft, thus holding it in the position to which it was moved.

Adjusting of any or all of the indexing means to change the broadcast station selection is accomplished in the following manner by the use of one hand only. 'Ihe control knob 23 is first pushed inward and rotated in the proper direction whereby the gear 81 is rotated to cause the bushing 19 to be screwed outwardly with respect to the shaft 1'| and the opening 8| in the end plate 3. The shaft 1| is prevented from rotating by the worm wheel which isengaged to the tuning shaft. As the bushing moves outward the blade |87 of the switch 8| is moved out of contact with the blade |19 which opens the circuit to the winding 6| and prevents energization thereof, which maintains the worm wheel in holding engagement with the tuning shaft. Outward movement of the bushing at the same time decreases the endwise compression between the pinions 89 and pinion washers 93 so that the only endwise force therebetween is that due to the Spring washer 91. The tuning shaft 35 -is then rotated to a new angular position by the manually rotatable knob i9 and worm gearing until the particular radio frequency desired is tuned in, which likewise causes the shaft 1| to be rotated to a new position. Rotation of the shaft 1| causes the pinions 89 to rotate therewith and move all the rack bars to a different position. The spring washer 91 exerts just sufficient endwise force 

